Writing Basic Sql statement Restricting & Sorting Data Single Row Function

1. SUPERVISION :
USTAZ. ASAAD

2. BSTC

3. Introduction :
• Structured Query Language (SQL) is the
standard language used to communicate with
database software.
• SQL is a complex and powerful language that
can be used to deal with databases.
• the ANSI standard requires the keywords to
all be similar (Select, Delete, Insert, and etc.).
This makes SQL universally understandable
and useable by all users.
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4. Slides contents
Writing Basic Sql statement
Restricting & Sorting Data
Single Row Function
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6. Writing basic Sql statement :
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7. Basic Select statement :
• SELECT distinct{‘ column
alias’}
FROM table_name;
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9. Using where clause
SELECT employee_id,
last_name, department_id
FROM employees
WHERE department_id = 90;
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10. Comparison conditions
< less-than SELECT * FROM employees WHERE salary <
2500;
>= Greater-
than-or-
equal-to
SELECT * FROM employees WHERE salary >=
2500;
<= Less-than-
or-equal-to
SELECT * FROM employees WHERE salary <=
2500;
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11. Comparison conditions (cont.)
= Equality
SELECT * FROM employees WHERE salary =
2500;
<> Inequality SELECT * FROM employees WHERE salary !=
2500;
> Greater-
than SELECT * FROM employees WHERE salary >
2500;
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12. Comparison conditions (cont.)
BETWEEN….
AND
SELECT first_name, last_name, salary
FROM employee
WHERE salary BETWEEN 1000 AND 1500;
LIKE SELECT first_name, last_name
FROM Employees
WHERE first_name LIKE 'S%';
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13. Comparison conditions (cont.)
IN SELECT first_name, last_name, job_id
FROM employees
WHERE job_id IN(‘IT_PROG', ‘CLERK');
IS NULL SELECT *
FROM employees
WHERE commission_pct is NULL
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14. Logical conditions :
Logical Conditions Example
OR SELECT last_name,job_id,salary
FROM employees
WHERE salary = 1400 OR job_id =
‘CLERK‘;
AND SELECT first_name,salary
FROM employees
WHERE salary >= 1000 AND salary <=
1500;
NOT SELECT first_name,job_id
FROM employees
WHERE NOT job_id = ‘IT_PROG‘;
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15. Order By Clause :
• Sort rows with the order by clause
• -ASC: ascending order ,default
• -DESC : descending order
• It’s comes last in the select statement
• SELECT expressions FROM tables WHERE
conditions ORDER BY expression [ ASC |
DESC ];
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16. Example :
Select last_name ,job_id
department_id,hire_date
From employees
Order by hire_date DESC;
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18. Function
Input
arg 1
arg 2
arg n
Function
performs action
Output
Result
value
Sql functions :
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19. Functions
Single-row
functions
Multiple-row
functions
Two types of sql fu nctions :
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20. Single row functions :
Single row functions:
• Manipulate data items
• Accept arguments and return one value
• Act on each row returned
• Return one result per row
• May modify the data type
• Can be nested
• Accept arguments which can be a
column or an expression
function_name [(arg1, arg2,...)]
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21. NumberGeneralDateCharacter
Four Single row functions :
Single-row
functions
conversion
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22. Character
functions
LOWER
UPPER
INITCAP
CONCAT
SUBSTR
LENGTH
INSTR
LPAD | RPAD
TRIM
REPLACE
Case-manipulation
functions
Character-manipulation
functions
Character functions :
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23. Case manipulating functions :
These functions convert case for character strings.
Function Result
LOWER('SQL Course') sql course
UPPER('SQL Course') SQL COURSE
INITCAP('SQL Course') Sql Course
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24. SELECT employee_id, last_name,
department_id
FROM employees
WHERE LOWER(last_name) = 'higgins';
Using Case Manipulation Functions
Display the employee number, name, and department
number for employee Higgins:
SELECT employee_id, last_name,
department_id
FROM employees
WHERE last_name = 'higgins';
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25. Character-Manipulation Functions
These functions manipulate character strings:
Function result
CONCAT('Hello',
'World')
SUBSTR('HelloWorld',1,
5)
LENGTH('HelloWorld')
INSTR('HelloWorld',
'W')LPAD(salary,10,'*'
)
RPAD(salary, 10, '*')
TRIM('H' FROM
'HelloWorld')
HelloWorld
Hello
10
6
*****24000
24000*****
elloWorld
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26. SELECT employee_id, CONCAT(first_name, last_name)
NAME,
job_id, LENGTH (last_name),
INSTR(last_name, 'a') "Contains 'a'?"
FROM employees
WHERE SUBSTR(job_id, 4) = 'REP';
Using the Character-Manipulation
Functions
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27. Number Functions
• ROUND: Rounds value to specified decimal
ROUND(45.926, 2)
45.93
• TRUNC: Truncates value to specified decimal
TRUNC(45.926, 2)
45.92
• MOD: Returns remainder of division
MOD(1600, 300)
100
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28. SELECT ROUND(45.923,2), ROUND(45.923,0),
ROUND(45.923,-1)
FROM DUAL;
Using the ROUND Function
DUAL is a dummy table you can use to view results
from functions and calculations.
1 2
3
31 2
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29. SELECT TRUNC(45.923,2), TRUNC(45.923),
TRUNC(45.923,-2)
FROM DUAL;
Using the TRUNC Function
31 2
1 2
3
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30. SELECT last_name, salary, MOD(salary, 5000)
FROM employees
WHERE job_id = 'SA_REP';
Using the MOD Function
Calculate the remainder of a salary after it is divided by
5000 for all employees whose job title is sales
representative.
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31. Working with Dates
• Oracle database stores dates in an internal
numeric format: century, year, month, day,
hours, minutes, seconds.
• The default date display format is DD-MON-YY.
SELECT last_name, hire_date
FROM employees
WHERE last_name like 'G%';
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32. Working with Dates
SYSDATE is a function that returns:
• Date / Time
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33. Arithmetic with Dates
• Add or subtract a number to or from a date for a
resultant date value.
• Subtract two dates to find the number of days
between those dates.
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34. Using Arithmetic Operators
with Dates
SELECT last_name, (SYSDATE-hire_date)/7 AS WEEKS
FROM employees
WHERE department_id = 90;
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35. Date Functions
Number of months
between two dates
MONTHS_BETWEEN
ADD_MONTHS
NEXT_DAY
LAST_DAY
ROUND
TRUNC
Add calendar months to
date
Next day of the date
specified
Last day of the month
Round date
Truncate date
Function Description
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36. • MONTHS_BETWEEN ('01-SEP-95','11-JAN-94')
Using Date Functions
• ADD_MONTHS ('11-JAN-94',6)
• NEXT_DAY ('01-SEP-95','FRIDAY')
• LAST_DAY('01-FEB-95')
19.6774194
'11-JUL-94'
'08-SEP-95'
'28-FEB-95'
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37. • ROUND(SYSDATE,'MONTH') 01-AUG-95
• ROUND(SYSDATE ,'YEAR') 01-JAN-96
• TRUNC(SYSDATE ,'MONTH') 01-JUL-95
• TRUNC(SYSDATE ,'YEAR') 01-JAN-95
Using Date Functions
Assume SYSDATE = '25-JUL-95':
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38. Conversion Functions
Implicit data type
conversion
Explicit data type
conversion
Data type
conversion
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39. Explicit Data Type Conversion
NUMBER CHARACTER
TO_CHAR
TO_NUMBER
DATE
TO_CHAR
TO_DATE
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40. Using the TO_CHAR Function with
Dates
The format model:
• Must be enclosed in single quotation marks and is
case sensitive
• Can include any valid date format element
• Has an fm element to remove padded blanks or
suppress leading zeros
• Is separated from the date value by a comma
TO_CHAR(date, 'format_model')
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41. YYYY
YEAR
MM
MONTH
DY
DAY
Full year in numbers
Year spelled out
Two-digit value for month
Three-letter abbreviation of the day of the week
Full name of the day of the week
Full name of the month
MON Three-letter abbreviation of the month
DD
Numeric day of the month
Date formats :
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42. Using the TO_CHAR Function with
Dates
SELECT last_name,
TO_CHAR(hire_date, 'fmDD Month YYYY')
AS HIREDATE
FROM employees;
…
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43. Using the TO_CHAR Function with
Numbers
These are some of the format elements you can use
with the TO_CHAR function to display a number
value as a character:
TO_CHAR(number, 'format_model')
9
0
$
L
.
,
Represents a number
Forces a zero to be displayed
Places a floating dollar sign
Uses the floating local currency symbol
Prints a decimal point
Prints a thousand indicatorBSTC

44. SELECT TO_CHAR(salary, '$99,999.00') SALARY
FROM employees
WHERE last_name = 'Ernst';
Using the TO_CHAR Function with
Numbers
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45. Nesting Functions
• Single-row functions can be nested to any level.
• Nested functions are evaluated from deepest
level to the least deep level.
F3(F2(F1(col,arg1),arg2),arg3)
Step 1 = Result 1
Step 2 = Result 2
Step 3 = Result 3
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46. SELECT last_name,
NVL(TO_CHAR(manager_id), 'No Manager')
FROM employees
WHERE manager_id IS NULL;
Nesting Functions
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47. General Functions
These functions work with any data type and pertain
to using nulls.
• NVL (expr1, expr2)
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48. NVL Function
Converts a null to an actual value.
• Data types that can be used are date, character,
and number.
• Data types must match:
– NVL(commission_pct,0)
– NVL(hire_date,'01-JAN-97')
– NVL(job_id,'No Job Yet')
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49. SELECT last_name, salary, NVL(commission_pct, 0),
(salary*12) + (salary*12*NVL(commission_pct, 0)) AN_SAL
FROM employees;
Using the NVL Function
…
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1
2
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50. Conditional Expressions
• Provide the use of IF-THEN-ELSE logic within a
SQL statement
• Use two methods:
– DECODE function
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51. The DECODE Function
Facilitates conditional inquiries by doing the work of an
IF-THEN-ELSE statement:
DECODE(col|expression, search1, result1
[, search2, result2,...,]
[, default])
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52. Using the DECODE Function
SELECT last_name, job_id, salary,
DECODE(job_id, 'IT_PROG', 1.10*salary,
'ST_CLERK', 1.15*salary,
'SA_REP', 1.20*salary,
salary)
REVISED_SALARY
FROM employees;
…
…
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53. Thank U
/alqaddal
/alqaddal
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Ahmed Alqaddal
Hamid Fadl
Baraah Alsayed